1. T cells in the immune system can be categorized into different types. What type of T cell directly kills infected body cells?

A. Helper T cells
B. Cytotoxic T cells
C. Regulatory T cells
D. Memory T cells

Correct answer: B

Rationale: Cytotoxic T cells directly kill infected body cells. These T cells recognize and destroy cells that are infected with viruses or other pathogens. They are crucial for eliminating threats within the body. Helper T cells, on the other hand, assist in coordinating the immune response by activating other immune cells. Regulatory T cells help maintain immune tolerance and prevent autoimmune reactions. Memory T cells are responsible for 'remembering' specific pathogens to mount a faster and stronger immune response upon re-exposure. Therefore, cytotoxic T cells are the correct answer as they directly target and kill infected cells.

2. Parkinson's disease is a neurodegenerative disorder affecting which neurotransmitter?

A. Dopamine
B. Acetylcholine
C. Serotonin
D. Glutamate

Correct answer: A

Rationale: The correct answer is A: Dopamine. Parkinson's disease is characterized by a progressive loss of dopamine-producing neurons in the brain. Dopamine is a neurotransmitter responsible for transmitting signals in the brain that control movement and coordination. A decrease in dopamine levels leads to the typical motor symptoms of Parkinson's, such as tremors, rigidity, and bradykinesia. Acetylcholine (option B) is involved in muscle movement but is not primarily affected in Parkinson's disease. Serotonin (option C) and glutamate (option D) are neurotransmitters that play different roles in the brain and are not primarily associated with Parkinson's disease. Therefore, the correct neurotransmitter affected in Parkinson's disease is dopamine.

3. What is the basic unit of heredity?

A. Chromosome
B. Cell
C. Gene
D. Organ

Correct answer: C

Rationale: Rationale: A gene is the basic unit of heredity that carries the instructions for making proteins, which determine an organism's traits. Genes are segments of DNA located on chromosomes within the cell. While chromosomes contain many genes, a gene itself is the fundamental unit of heredity responsible for passing on genetic information from one generation to the next. Cells are the basic structural and functional units of living organisms, but genes specifically carry genetic information. Organs are composed of tissues and serve specific functions within an organism, but they are not the basic unit of heredity.

4. What happens to the speed of a sound wave when it travels from air to water?

A. It increases because water is denser.
B. It decreases because water is denser.
C. It remains the same.
D. Speed depends on the frequency, not the medium.

Correct answer: A

Rationale: Sound waves travel faster in denser mediums like water compared to air due to stronger interactions between particles.

5. Which property of a substance refers to its ability to be hammered or pressed into thin sheets without breaking?

A. Malleability
B. Ductility
C. Viscosity
D. Conductivity

Correct answer: a

Rationale: Malleability is the property that describes a substance's ability to be hammered or pressed into thin sheets without breaking.

6. Which of the following is the primary function of the cell membrane?

A. To provide structural support for the cell
B. To transport substances in and out of the cell
C. To synthesize proteins and lipids
D. To store genetic material

Correct answer: B

Rationale: Rationale: The cell membrane, also known as the plasma membrane, plays a crucial role in regulating the movement of substances in and out of the cell. It is selectively permeable, meaning it allows certain molecules to pass through while blocking others. This function is essential for maintaining the internal environment of the cell and ensuring that necessary nutrients can enter the cell while waste products and other substances can exit. While the cell membrane does provide some structural support for the cell, its primary function is to control the transport of substances. The synthesis of proteins and lipids primarily occurs in other cellular organelles such as the endoplasmic reticulum and Golgi apparatus, while storing genetic material is the function of the nucleus.